In Cascassonne, 1942, spirited young woman Sandrine finds herself drawn into the world of the Resistance. Her network - codenamed Citadel - is made up of women willing to risk everything to fight the German Occupation. Her fate is tied up with that of three very different men, and just what is the ancient secret that has drawn generations of people to the Pyrenean mountains? 'A thrilling adventure and a truly epic love story' Kate Saunders, "The Times"